Programs

Field99

This version of the program became stable on Feb 26, 1999. This was for the HMS-100 tune. The codes are field99.f and params.f . The codes are stored in /home/cdaq/FIELD/Archive_99 on the cdaq machines.

Field00

The field99.f code was changed to modify the setting of the HMS Q3 current, because a zero current offset was found in setting Q3. This was done on July 19,2000 and is logged in hclog book entry 27270. The set current for Q3 was modified as:

$$I_q3 = I_q3/(1.0107*(1.004-0.0136/hpcent_set))$$ (1)

The resulting change over corrects the offset , but it still an improvement. This modification is put in field00.f. It still uses params.f. Now the codes are stored in /home/cdaq/FIELD/Archive_00 on the cdaq machines.

Field02

By looking at elastic $ep$ data, Eric Christy found that there was no saturation in the HMS dipole field above momentum of 3.56 which was contrary to expectation. So a new params02.f was created which commented out the line which modified HMS dipole field when setting above 3.56 GeV/c . There is a new field02.f which is just a copy of field00.f . The codes are stored in /home/cdaq/FIELD/Archive_02 on the cdaq machines.

Field03

Eric Christy found that the true HMS central momentum, $hpcent\_true$, was 0.997 times the set HMS central momentum,$hpcent\_set$, by analyzing a large number of elastic $ep$ data sets. So

$$hpcent\_true = hpcent\_set*(1-0.003)$$ (2)

So to get the true momentum, the setting of the dipole field should be divided by (1 - 0.003), since the dipole field setting is proportional to the momentum. So field02.f was modified into field03.f, with the change that all the magnet settings were divided by (1 - 0.003). One needs to scale the quads to keep the Q/D ratio the same. This means that the magnets settings are the same for field03 when $hpcent\_set$ = 0.997 as with field02 $hpcent\_set$ = 1.0 GeV/c . The params02.f was copied to params03.f. The codes are stored in /home/cdaq/FIELD on the cdaq machines. To compile the code

make -f makefile03